Apparatus for and method of installing sub-surface moisture barrier in soils



AVERAGE HEIGHT OF PLANTS (INCHES) July 30, 1968 v w. R. THOMPSON ETAL 1-3,394,551

APPARATUS FOR AND METHOD OF INSTALLING SUB-SURFACE A MOISTURE BARRIER INSOILS Filed Oct. 20, 1966 SUB'SURFACE MOISTURE BARRIER IN SOILS TESTPLANTS'BARRIER AT 9 men HEIGHT o CONTROL- wmaour BARRIER DEAD o, I l l ll l I I I o 5 IO I5 so as 4s DAYS mom PLANTING F lG.-I.

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| SPRAY SPGRAY LA;ER

Willibm R. Thompson Brian Adams nventors Patent Attorney United StatesPatent C 3,394,551 APPARATUS FOR AND METHOD OF, INSTALLING SUB-SURFACEMOISTUREBARRIER IN SOILS William R.' Thompson and Brian Adams, Sarnia,Ontario,

Canada, assignorsto 'Esso Research and Engineering Company, acorporation of Delaware Continuation-impart of application Ser. No.228,162,

Oct. 3, 1962. This application Oct. 20, 1966, Ser.

. 4 Claims. (Cl. 611) This application is a continuation-impart of US.Ser. No. 228,162, filed Oct. 3, 1962, now abandoned.

The present invention is concerned with an improved method and apparatusfor increasing crop yields in semiarid regions, utilizing a particulartechnique of providing a moisture barrier in soils. In particular, thisinvention relates to a novel improved method and apparatus formaximizing 'crop'production from a given acreage in semiarid regionswhich receive an insuflicient amount of natural rainfall to ensure seedgermination and to sustain the growth of such crops without irrigationby conserving and utilizing the" moisture common to such acreage throughnatural means.

The invention is specifically concerned with a technique for theprevention of moisture loss by seepage particularly in sandy soils. Abarrier composed of a petroleum product or other suitable imperviousmembrane is laid down at a critical and predetermined distance below thesurface. This membrane, as for example a petroleum barrier, functions toprevent the rapid loss of water downwardly by drainage and to retain itnear the surface and agriculture roots, thereby making sandy areasuseful for agriculture.

In the United States and Canada there exist millions of acres ofpotentially valuable crop lands which do not receive sufiicient rainfalland which in many cases idrain olfmoisture very rapidly due to the highporosity of the soil. Also, wind erosion and other climatic conditionshave served to accentuate these lack of moisture problems. Thus, in manyparts of the world the land is barren of useful vegetation because ofthe lack of water. However, in many of these places the lack of moistureis not due to insuflicient rainfall but is due to the fact that the soilis mainly sand and has very poor moisture-retaining properties.Therefore, in accordance with the present invention, a barrier such aspetroleum asphalt is deposited at a critical distance below the earthssurface. This barrier functions to prevent the rapid loss of waterdownwardly in the soil and retains it near the surface and the growingroots, thereby making agriculture possible. The process and technique ofthe present invention may be readily understood by the followingexamples illustrating the same.

In these tests, two wooden boxes 12" x 18" by 14" deep with slits in thebottom to allow drainage were used to hold experimental seed beds. Theseed beds were prepared from a coarse sand obtained at the groundsurface near Lake Huron. In Example 1, the box Was filled with sand to adepth of about 9 inches. Then the surface was tampeid level and sprayeduniformly with 40 grams of an asphalt-water emulsion. The barrier wasprepared with 40.0 grams of a 50/50 emulsion of asphalt and water. Thebarrier 12" x 18" in area was then composed of 20 grams of asphalt.Approximately 3 /2 inches of sand were then placed above the barrier. Acontrol box was prepared by simply filling with sand to a depth of 12inches. In each box was planted corn and soya beans all at a depth of 1/2 inches. The boxes were placed on the rooftop in full sunlight with aclear plastic cover above to keep out rainfall. Water was added bysprinkling each at intervals, with the same carefully measured volume ofwater. Interval and volume were scaled to the rainfall at Tegiura, Libyaduring the rainy season during the 1961 period.

3,394,551 Patented July 30, 196 8 2 1 am le 1 In this test wherein theasphalt barrier was placed about 3 /2 inchesbelow the surface. of'thesandy soil; within six days the crops planted in the terrain containingthe barrier germinated, whereas thecrops inthe, ter; rain not containingthe barrier did notgerminate until ten days later. For the first fourweeks the crops planted in the barriered area grew to about six inchesin height as compared to the three inches of height attained by .thecrops in the area not containing the barrier.

However, during the month of May zwhen the rainfall approximated 0.28inch, the corps in the terrain containing the barrier wilted and died,whereas .the crops in the areas not containing the barried lived. I

Exalmple 2- In a second test conducted during May, June. and .Iuly

under identical conditions described with respect to .Example 1 exceptthat the barrier was placed about 9 inches below the surface, all cropsgerminated in approximately the same time, and the height attained bythe respective crops was approximately the same within the first twoweeks. However, in the succeeding dry six-week period the crops in theterrain containing the barrier thrived to the extent of reaching aheight of 24 inches for the corn and 12 inches for the beans as comparedto complete failure of the crops in the area not containing the barrier.The results are tabulated in the following table and graphicallyillustrated in FIGURE 1.

GROWTH OF CORN Height of Corn (Inches) From the foregoing it is evidentthat, when the barrier was only 3 /2 inches below the surface themoisture was retained too close to the surface and during the dry hotspell, rapid evaporation of the retained moisture occurred, resulting inthe wilting and dying of the crops. On the other hand, in Example 2 whenthe barrier was 9 inches below the surface, this rapid evaporation didnot occur as the moisture was retained at a deeper level and the cropsmade good progress.

As mentioned above and illustrated by the examples, the position of thebarrier with respect to the surface is critical, i.e. the barrier mustbe far enough below the surface so as to prevent the rapid evaporationof moisture. As a minimum depth the barrier should be at least about 8to 14, eg 9 to 12 inches below the surface of the soil. Of course, thebarrier may and in some applications will be at a depth greater than theminimum depth. For example, the barrier may be at depths of up to about2 to 3 feet below the surface. The optimum depth for any particularapplication will be influenced of course by several factors such as theparticular crop, the soil composition etc.; but will in all applicationsbe at least as deep as the described minimum depth. For most commoncrops such as beans, corn, tomatoes, potatoes, etc., and the like, the

bafliqrwill not need to be as deep as when used with trees, such asfruit trees.

As pointed out heretofore, the barrier is preferably a petroleumproduct, as for example, a petroleum asphalt film or a wax film. Thebarrier may comprise a heavy crude or other type of suitable membrane.The preferred type of asphalt fil'm is applied as an asphalt-in-wateremulsion wherein the amount of asphalt present in the emulsion is in therange from about 20 to 65 preferably in the range from about 40 to 55%by weight.

' The laying of the barrier at the desirable depth can be accomplishedin a number of ways. For example, a rig similar in operation to a seeddrill or an ammonia drill is designed to inject a suitable liquidproduct at the desired depth. Also, deep cutting ploughs with a sprayingtube at the trailing end of the base can be used to spray the bottom'ofthe furrow as it is ploughed. A thin steel foil may be pushed throughthe ground by a bulldozer and the product sprayed into the ground fromthe trailing edge of the foil.

' A mechanical machine or device can be used similar to that used inroad building wherein the required depth of top soil is momentarilylifted at the front of the machine as it moves forward and wherein therequired film is positioned and placed at an intermediate point withinthe machine and wherein the top soil removed at the front of the machineis replaced at the rear of the machine. A machine such as this isillustrated in FIGURE 2 and functions as follows: The sand scoop 1penetrates below the ground surface about one foot, and as the machinemoves forward, the surface sand is scooped up and carried overhead inthe sand carrier system 5. At the same time the surface of the shallowtrough formed is sprayed with liquid asphalt by spray equipment 2.Immediately behind the asphalt spray is a sand spray 6 which spreads athin covering layer of sand over the asphalt. A roller 4 follows thesand spray and comprises the asphalt sand mixture into a tight barrier.The bulk of the sand is dropped back over the barrier from the rear ofthe machine, thus completing the operation. Thus, an asphalt barrier 7is readily positioned below the surface of the soil 8.

What is claimed is:

1. A method of placing a substantially continuous moisture barrier stripat a predetermined distance beneath the surface of the soil in order toimprove the growth of crops above said moisture barrier strip whichcomprises the following steps in combination,

(a) removing surface soil to said predetermined distance thereby forminga continuous trough,

(b) temporarily storing said removed surface soil,

(c) spraying a liquid petroleum product in said trough,

thereby substantially covering the bottom of said trough with a layer ofliquid petroleum product,

(d) spraying a portion of said stored surface soil onto said layer ofliquid petroleum product, thereby forming a thin layer of soil over saidlayer of liquid petroleum product,

(e) compressing said thin layer of soil and said layer of liquidpetroleum product, thereby forming a substantially continuous moisturebarrier, and

(f) filling said trough with the remaining portion of said storedsurface soil.

2. A method as defined by claim 1 wherein said liquid petroleum productcomprises an asphalt-in-water emulsion. 1

3. A method as defined by claim 1 wherein said predetermined distance isat least 8 to 14 inches below the surface.

4. A mobile apparatus for continuously laying a moisture barrier at apredetermined distance below the surface of the ground in order toimprove the growth of crops above said barrier, which comprises incombination (a) scoop means so constructed and arranged to penetrate theground surface said predetermined depth, remove soil at the point ofpenetrationv to form a trough in the ground and convey said soilelsewhere in said apparatus,

(b) spray assembly means comprising tank means constructed and arrangedto hold a liquid form of a moisture barrier and spray means constructedand arranged to spray said liquid to form a layer of moisture barrier atthe bottom of said trough,

(c) soil spray means constructed and arranged to spray a small amount ofsoil on the top of said barrier in said trough,

(d) compression means so constructed and arranged so as to compress saidbarrier and soil combination,

(e) covering means adapted and constructed to fill in said trough aftersaid compression, and

(f) conveyance means for moving said apparatus along the ground andwherein said soil-removing means and said soil-replacement means areconnected with conduit means.

References Cited UNITED STATES PATENTS EARL I. WlTMER, Primary Examiner.

1. A METHOD OF PLACING A SUBSTANTIALLY CONTINUOUS MOISTURE BARRIER STRIPAT A PREDETERMINED DISTANCE BENEATH THE SURFACE OF THE SOIL IN ORDER TOIMPROVE THE GROWTH OF CROPS ABOVE SAID MOISTURE BARRIER STRIP WHICHCOMPRISES THE FOLLOWING STEPS IN COMBINATION, (A) REMOVING SURFACE SOILTO SAID PREDETERMINED DISTANCE THEREBY FORMING A CONTINUOUS TROUGH, (B)TEMPORARILY STORING SAID REMOVED SURFACE SOIL, (C) SPRAYING A LIQUIDPETROLEUM PRODUCT IN SAID TROUGH, THEREBY SUBSTANTIALLY COVERING THEBOTTOM OF SAID TROUGH WITH A LAYER OF LIQUID PETROLEUM PRODUCT, (D)SPRAYING A PORTION OF SAID STORED SURFACE SOIL ONTO SAID LAYER OF LIQUIDPETROLEUM PRODUCT, THEREBY FORMING A THIN LAYER OF SOIL OVER SAID LAYEROF LIQUID PETROLEUM PRODUCT; (E) COMPRESSING SAID THIN LAYER OF SOIL ANDSAID LAYER OF LIQUID PETROLEUM PRODUCT, THEREBY FORMING A SUBSTANTIALLYCONTINUOUS MOISTURE BARRIER, AND (F) FILLING SAID TROUGH WITH THEREMAINING PORTION OF SAID STORED SURFACE SOIL.